Valve and valve gear for engines



Sept. 7, 1937.

4 Filed Aug' s. L. G. jvALvE ANnvALvE GEAR FOR` ENGINESl KNOX 6 'Sheets-Sheet l l N VEN TOR. Samia? Z. f 75am( y WX/MQZWWM TORNE YS.

Si. L. G. KNOX VALVE AND VALVE GEAR FOR'ENGINES 6 Sheets-Sheet 2 Filed'Aug. 2l, 1935 fifi, 7

INVENTOR. Sav/mld 'Z/. Gli/war.

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RNEYS.

Sept. 7, 1937;

Ill/llaa A Sept. 7, 1937. s. L. G. KNOX Y "2,091,996

VALVE AND VALVE GEAR FOR ENGINES l Fil'ed Aug. 2l, 1935 6 Sheets- Sheet 3 l v "Ln- 7 T l 1 i I f "m" "mi Lg l o L... Ml /f 7 A TToRNEx/S.

sept.7,1937. l s. L.. G/KNox 2,091,996

VALVE AND `VALVE GEAR FOR ENGINES Filed Aug. 21, 1955 s sheets-sneer -4 INVENToR l ATTORNEYS.

Sept. 7, 1937. s. L. G. KNOX VALVE ANDVALVE GEAR FOR ENGINES Filed Aug. l22|., 1935 6 Sheets-Sheet 5 INVENToR. BY/wfwf/LW ATTORNEYS.

Isept'.7,1937. l 5;... G. KNOX `v2,091,996

VALVE AND VALVE GEAR FOR ENGINES .Filed Aug. 21,;1935 e sheets-sheet s INVENTOR.4 amael L. ynox.

ORNEYS.

Patented Sept. 7, 19377 oNirED srA'rE PATENT oFFlcE My invention relates to -new and useful improvements in valves for elastic duid-pressure engines, and in the valve-gear associated therewith. More specifically it 4relates to a reciprocating valve-assembly for engines utilizing steam or air or other elastic fluid as the operating fluid. Merely for illustration, the following description relates `to my invention primarily as adapted to a steam engine.

It is'the principal object of my invention to provide means whereby the valve shall cut olf the-operating iluid (which may be steam) at a point in its return stroke, different ,from the point in its advance thesteam, whereby to obtain certain advantageous results automatically,` one ofv Vwhich is an eiectively later cut-ofi' during starting and when engine is slowed down during other times of relatively greater torque resistance.

Conversely, in an engine such as a multi-cylindersteam-reverse engine, asis described in my Patent 1,845,288, where the position of the eccentric is limited tofa very r`narrow range of angular position, the present invention, reversed in its operation, can be employed to effect a shorter cut-oil so as to increase the expansion ratio with consequent improved economy.

In addition to the' above-stated objects, I have worked out a. number of -novel and useful details, which. will be readily evident as the description progresses.

l My invention consists in the novelparts, and.

in the combinations and arrangements thereof, which are defined in the appended claims; and of which three embodiments are exemplified in the accompanying drawings, which are herein- 4after particularly described and explained.

Throughout the description, the same referi ence-number is applied to the same member or valve chamber and part of the corresponding A to'similar members.

Referring to the drawings, Figures 1 to 8 inclusive are side elevations of one embodiment of my invention, showing the stroke at which it admits l it will be seen that:

show six successive positions of tli'evalve in an operating cycle. f I

Figures 16 to 21 inclusive are plan views of a third embodiment of my invention, showing a l portion of valve-seat and valve. These figures show six successive positions of the valve in an operating cycle.

Figure 22 isA an elevation, partly in section, taken along the line 22-22 in Figure 1.

Figures 23 to 27 inclusive are plan viewsof a slight variant of the second embodiment of my invention. These iive figures show iive successive positions of the valve in an operating cycle.

.Referring -now to the iirst variant, which for purposes of identification I shall call the supplementary opening" variant, namely that of Figures 1 to 9'inclusive, I shall apply all the reference numbers to Figure 1 only.- In the other figures, I shall apply only such reference numbers as may be necessary -to describe the progressive operation of my device. y

3i is a. piston, reciprocating in steam-cylinder 32, and operating a piston-rod 33, and thereby gperating a connecting-rod 34, and a crank-disk s.

The rotation of the crank-disk 35 imparts a compound motion to valve-stem 36, by means of a linkage which will now be described.

Links 31 and 38 are respectively pivoted at so from the side of the valve-stem 36, eccentrically ,35

. at 46. The other end of link 44 is pivoted at 41 to an intermediate point on ,link 4I. Link 44 is pivoted adjacent its center at 48l to one end of link 31. e

- The result of all this linkage is that, as the crank-disc l5 rotates, the valve-stem 36 is given a combined reciprocating and rolling motion, which it imparts to the valve 49.

Although the particular linkage herein described and shown is not an essential part of this variant 'of my invention, the provision of thatlinkage or of some other means, to produce a combined rolling (or transverse) and reciproeating motion is essential.

The valve moves in a steam-chest 50, into each end of which steam is admitted through branched pipe 5 I and from which the exhaust steam leaves by pipe 52.

For a detailed description of the valve and the' ports which itcovers` and uncovers, turn l identilcation'herein they will be called suppleder. Port 54 leads to the right-hand end of the' Y5 cylinder.

Ports 55 are exhaust-ports leading to pipe 52. For identification herein, I shall call all of the surface of the valve-seat, other than its ports, a bridge.

vThe valve proper is in two parts, in each of which there is a small 'right-angled hole 56, 51, extending from the hat end face of the valve to the curved side of the ivalve. The purpose of these holes is to delay the point of cut-off during times of relatively greater torque resistance. For

these two supplementary openings, with the peculiar motion of my valve.

By a, successive inspection of Figures 1 to 8,

it will be seen that, due to the combined recipro cation and rolling motion yof the va1ve,'each"supplernentary opening described a substantially elliptical path on the inner curved surface of the valve-cy1inder,'which surface serves as a valve seat. Eight successive positions of each supplementary opening on its substantial ellipse are plotted in Figure 9, the numbers referring to the ilgure in which the supplementary opening occupies the numbered position.

Let us now follow the valve 49 and piston 3| through their cycle, as shown successively in Figures 1 to 8. In all the gures, the crankdisk 35 is rotating clockwise.

4()A In Figure 1, the piston 3| is in midstroke and is moving to the left, as is indicated by the arrow above it. The valve 49 is just short of center, travelingv to the right, as indicated by the arrow at the end of the valve-stem 36. All .ports are closed, and neither supplementary opening is functioning.

In Figure 2, the piston 3| has now traveled against compression to the left-hand end of its cylinder, and is stopped, as is indicated by the 50 zero above it. The valve 49 has moved slightly to the right of its former position, and is just about to uncover the left-hand port to admit l steam to the left-hand end of the cylinder, and has uncovered the right-hand port to permit exhaust steam to pass out through the exhaust ports. 'I'he supplementary openings are still not functioning, because supplementary opening 56, dueto the orientation of the valve, is passing above port 53, and supplementary opening 51 is wholly to the rightA of port 54. f

l 70 In Figure 4, the valve 49 has begun to move to the left. Exhausting from the right-hand end of the cylinder is still continuing. The lefthand admission is now closed, but the left-hand supplementary opening has now rolled down- `75 wardly, and` has moved to the1eft into a posithe right.

tion in which it continues to admit steam from the left-handend of the steam-chest vinto the I left-hand admission-port 53.

It is to be noted that in Figure 4, the valve is in exactly the same position, so far as reciprocation alone is concerned, as it was in Figure 2; but, owing to its In Figure 5, the piston 3|, still moving to thev right, 'is in mid-stroke. 'I'he valve 49 is just short of center, traveling to the left. All ports are closed. The left-hand supplementary opening has just ceased to function, and the vrighthand supplementary opening has not yet begun to function.

In Figure 6, the piston 3| has now traveled against compression to the right-hand end ofv lits cylinder, and has come to a stop, as s'indicvated by the zero written above it. The valve 49 has moved slightly to the left of its latestvposition, and is just about to uncover the right-hand port to admit steam to the right-hand end of the cylinder. and has uncovered the left-hand port to permit exhaust steam toy pass out through the exhaust-ports. 'I'he supplementary openings are still not functioning, because supplementary opening 5l is passing below port 54, and supplementaryopening 56 is by now wholly to the left of port 53.

In Figure '7, the valve 49 is in its extreme lefthand position, with full admission to the righthand end of the cylinder, and full exhaust from the left-hand end of the cylinder; and accor-dingly the piston 3| has begunits. movement to the left. Both supplementary openings are still out of contact with their respective ports, but note that supplementary opening 51 is rolling up `onto a level with port 54.

In Figure 8, the valve 49 has begun tomove to Exhaust from the left-hand end of the cylinder is still continuing. The right-hand admission is now closed, but the right-hand supplementary opening has now rolled upwardly and moved to the right into a position in which it continues to let steam from the right-hand end of the steam-chest into the right hand admission-port 54.

This completes the cycle. Reverting now to Figure 1, we see that all ports are closed, the right-hand supplementary opening has now ceased to function, and the left-hand supplementary opening has not yet begun to function.

Thus the eight positions may now be summarized as follows:

1. All ports closed. Supplementary openings -not functioning.

2. Left-hand admission about to start. Righthand exhaust open. I

3. Left-hand admission and right-hand exl haust open.

1. Right-hand exhaust still open. Left-hand admission-ports closed, but steam still being admitted through left-hand supplementary opening', which is now functioning.

5. Everything nally closed again.

6. Right-hand admission about tol start. Lefthand exhaust open.

7. Right-hand admission andv left-hand exhaust open.

8. Left-hand exhaust still open. Right-hand admission-ports closed, but steam still being admitted through right-hand supplementary opening, which is now functioning.

1. Everything finally closed again. Reverting now to the left-handv ellipse of Figure 9, we see that, owing tothe action `of the supplementaryopening, admissionl to the left-v hand .end 'of the cylinder continues until the valve has traveled back to the left to a position (5) considerably beyond the ,position (2) at' which l() admission began, l

This delayed cut-off is one of the principal features of my invention.

Similarly, from the right-hand ellipse of Figspeeds up, only a diminishing amount of steam is admitted'through the supplementary opening between positions 4 and 5, and thus my point of cut-olf automatically'shifts back towards position 4. When the engine has reached full speed, only a very small proportion of the steam passes through the supplementary opening with the resuit that the eft'ectivepoint of cut-oli is shifted to a position. substantially that shown in Figure ,4. It is to be noted that this entire action of the supplementary opening is acomplished without altering the setting of any part. Similarly as to ,35 my right-hand supplementary opening.

It should be evident from the above description that the same result would be obtained, if the cylindrical interior of the steambox were developed (in the 'geometrical sense) to constitute 4o a ilat valve-seat, and .if the valve were likewise developed to contact it, and thenwere constrained (in any convenient manner) to follow a substantially elliptical course during its reciprocation.

Similarly the supplementary opening could be cut in the form of a notch, either in the cylindrical form of my device, orl in the developed" flat form. Compare the variant of Figures 16 to 21, hereinafter discussed.

-' or my invention has been `disclosed, that any rotary motion o f my cylindrical valve, regardless whether rolling back and forth as described and shown herein, or continuously rotating, would accomplish the same end, provided that it constrained my supplementary openings to trace a closed curve, properly located with respect to my admission-ports. `Accordingly I 1'se the word rotary in my claims in this broad sense.

yThis leads us to the variant of Figures 10 to 15, in which 6i is a portion of a flat valve-seat, and 62 is the correspondingportion of a flat valve. For convenience this variant will be known as the "turreted variant.

65 The valve 62 is constrained (in any convenient manner) to move in a substantially elliptical path .when reciprocated. To illustrate this movement, a small circle has been drawn about .a given point .of the vvalve in each of the six figures, and the course of this-point has been plotted in dash-dot lines, with a curved arrow to indicatethe direction of travel.

. The turreted left-hand edge of the valve .62

uncovers rectangular admission-ports 63 in valve-seat 6i. v

have of course remained closed.

It should be evident, now that this variant lIn Figure 10, admission is about to begin.

VFigures 11 to 14 show successive stages of admission; and cut-off takes place in Figure i5. During the passage from the position of Figure 15 to a repetition oi that of Figure y10, the ports By comparing the angle indicated by arrows in Figure 10, with that similarly indicated in Figure l5, it will be'seen that, when cut-off occurs, the valve has traveled back to the left far beyond the position at which admission occurred when the valve was'travelingto the right.

By changing the location, size and/or shapey of the ports and/or ofthe turreted edge of the valve, it is possible to regulate the degree of opening in various positions, thereby obtaining any desired one'of a wide range of characteristics of engine acceleration.` For example, by shifting the edge 64 of the turrets toward the foot of the page a slight vdistance as shown in Figures 23 to 27, practically thesame effect of admitting a diminishing amount of steam can be accomplished as with the supplementary ports of the first variant; and, as there, this occurs without the alteration of the settingof any part.

Figure 23 corresponds to Figure l0; none to Figure 11; Figure 24 Ytoligure 12; Figure 25 to Figure 13; Figure 26- to Figure 14; and Figure 27 to Figure 15. 64a represents the thus relocated valve-edge. It will be noticed that this relocatic l does not alter the degree of valve opening in the positions of Figures 10 (23), 11, l2 (24),

4 and l5 (27); anddoes not appreciably alter it in the position of Figure 13 (25). Yet, in the position of Figure 14 (26), it has the effect of'a supplementary opening, as in the first Yand third embodiments of my invention.

It should be evident from the above description that the turreted device of Figures l0 to 1,5, or of Figures 23 to 27,v could be enveloped (in the geometrical sense) upon the cylindrical surface and cylindrical interior respectively of the valve and steam-.chest of Figures 1 to 9.

As in the case of the first variant, I shall call that part of the valve-seat other than the ports 63, a brid'ge.

This leads us to the variant of Figures 16 to 21, in which 1I is a portion of a fiat valve-seat, and 12 is the corresponding portion of a fiat valve.

For convenience this variant will be knownas the serrated variant.

The valve 12 is constrained (1n any convenientmanner) to rnove in a substantially elliptical path when reciprocated. To illustrate this movement, a small circle has been drawn about l a given point of the valve in each of the six figures, andthe course of thispoint has been plotted in dash-dot lines, with 4a curved arrow to indicate the direction of travel.

The serrated left-hand edge of the valve 12 uncovers rectangular admission-ports 13 in valveseat 1I.

In Figure 16,'admission is about to begin.

Figures 17 to 19 show successive stages of'admission; and cut-ofi` takes place in Figure 20.

During the passage from the position of Figure By changing thelocation, size and/or shape double 20 to a repetition of that of Figure-1.6, thel ports 

